For example, in a manufacture of an FPD (flat panel display), a circuit pattern is formed by a so-called photolithography process.
In the photolithography process, a predetermined film is formed on a substrate to be treated such as a glass substrate, and then a photoresist (hereinafter, referred to as a resist or a resist solution) being a treatment solution is applied to form a resist film (photosensitive film). Then, the resist film is exposed to light corresponding to the circuit pattern, and subjected to developing treatment to form into a pattern.
As a method of applying the resist solution to the substrate to be treated to form the resist film in the photolithography process, there is a method of discharging the resist solution in a band shape from a discharge port in a slit shape to thereby apply the resist on the substrate.
A conventional resist coating apparatus using this method will be briefly described using FIG. 29.
A resist coating apparatus 200 illustrated in FIG. 29 includes a stage 201 on which a substrate G is mounted, a resist supply nozzle 202 that is arranged above the stage 201, and a nozzle moving means 203 that moves the nozzle 202.
The nozzle 202 is provided with a discharge port 202a in a slit shape having a small gap extending in a width direction of the substrate G, and configured to discharge a resist solution R supplied from a resist solution supply source 204 from the discharge port 202a. 
However, the discharge port 202a in a slit shape is formed of the small gap and is therefore susceptible to clogging due to drying up of the resist solution if a nozzle tip (discharge port 202a) after coating treatment is left as it is, and cannot perform uniform discharge in the nozzle width direction any longer as illustrated in FIG. 30.
Therefore, the resist coating apparatus 200 includes a priming means 208 configured to prepare the state of the resist solution R that adheres to the nozzle tip and remains after the coating treatment as illustrated in FIG. 29.
The priming means 208 is for discharging, before the coating treatment on the substrate G, the resist solution R to the surface of a rotatable priming roller 207 in a cylindrical shape to uniformize the resist solution R adhering to the nozzle tip (hereafter, referred to as a priming treatment).
In this configuration, in the resist coating treatment on the substrate G, the resist solution R is discharged in a band shape to the entire surface of the substrate G from the discharge port 202a in a slit shape while the nozzle 202 is being horizontally moved by the nozzle moving means 203, whereby the coating treatment of the resist solution R is performed.
Further, in the waiting time of the nozzle 202, the priming treatment of the nozzle 202 is performed by the priming means 208. In the priming treatment, the resist solution R uniform in the substrate width direction is made to adhere in a bead line shape on the rear side in the coating direction of the discharge port 202a of the nozzle 202, thereby making it possible to perform uniform coating treatment from the start time of the next coating treatment.
Note that the resist coating apparatus is described in Patent Document 1.